Conventional personal computers are very noisy devices. The main source of the noise generated by a conventional personal computer is the cooling fan in the computer housing. The fan is needed to provide air-cooling to the components enclosed in the computer housing. Cooling is especially important for the microprocessor integrated circuit (IC) of the computer. As the microprocessors in modem computers become more and more powerful, the device density of the microprocessor IC's has become very high. Without proper cooling, the heat generated by the large number of devices in the microprocessor IC can quickly cause the IC to overheat and damage the IC. Another component that generates a significant amount of heat (as well as noise) is the hard drive, which is constantly spinning when the computer is in the operational state to allow quick disk input/output. To remove all the heat generated by the components in the computer housing, which can be up to several hundred watts, the fan has to be fairly powerful, i.e., rotating at a high speed to generate an air stream that flows through the computer housing at a high rate. The noise of the airflow and the mechanical vibration of the fan form a main part of the loud noise of a conventional personal computer.
The loud noise of conventional fan-cooled computers is highly undesirable. The noise emitted by a personal computer in either a home or office is distracting and annoying, and can have negative effects on the productivity of the users. Even if the users can try to mentally tune out the noise, it may still affect them physically and mentally. Also, consumers are often reluctant to place a personal computer in areas of the home where the loud noise can interfere with activities such as listening to music or sleeping. The loud noise may also directly affect the usefulness of fan-cooled computers in many applications. For instance, noise emission from a computer affects the signal-to-noise ratio (SNR) of an embedded microphone in the computer, making voice input less reliable. Also, despite the powerful capabilities of modem personal computers for processing music data, a fan-cooled computer is typically too loud to be used directly in a recording studio, and would require the to run the microphone to another room to avoid the noise.
Thus, the reduction or elimination of the loud noise generated by the cooling fan in a computer can potentially improve the productivity of computer users in both the office and home settings, and make the computer usable in applications where noise is a concern. Moreover, the willingness of consumers to place a personal computer anywhere in the home or work place is essential to the success of personal computers of future generations. The removal of the loud noise of today's fan-cooled computers can be a significant factor in achieving that goal.
Besides the noise, using a fan to provide cooling has other drawbacks. The fan itself is operated by electrical power from the computer power supply and thus increases the power consumption of the computer and adds heat to the total amount of heat it is to remove from the computer. Another significant problem with fan cooling is that the fan becomes a single point of failure of the computer. If the fan is broken, the entire computer becomes unusable.